C / C++ / MFC

Re: C++ Program without main()

7-Jun-12 0:12

In standard C++ it isn't possible.

As Richard mentioned you can specify an entry point for MSVC and other linkers allow you to do the same thing but you'll have a few hurdles to jump:

- The parameters to whatever function you define as the entry point will probably not be argc and argv
- Depending on the start-up code you're avoiding static and global objects may not be initialised (no great loss though)
- The language runtime library, even if linked, probably won't be initialised
- Anything that relies on the OS interacting with the language might go screwy (e.g. if new/delete expects allocations to come out of a heap the runtime allocates on start-up)

About the only place I've used this trick, had it work and be useful was back programming for Windows 3.1 when I was trying to keep the size of code down to a minimum and I was willing to pay the price for having an emasculated language. Basically if you're happy programming in assembler and using the OS and your own code for everything then then it may have some use.

Aescleal13-Jun-12 16:50

What's problem of my code?( create a random maze)

13-Jun-12 16:50

Hi Mr. Univoter, any chance you can tell me why you voted me down? This is so I can either/or:

- improve my answer and perhaps leaarn how to express myself better next time
- learn something
- disagree with you and say why and let other people make up their mind

I don't do tit for tat univoting so don't let that stand in your way!

Ash

Dump analysis

HungryCPPDev6-Jun-12 21:22

HungryCPPDev

6-Jun-12 21:22

Hello All,
I have a hang dump from client. But the corresponding pdb are not available as it is a legacy project.
Is it possible to know whether my components are responsible for this hang without pdb's.

Thanks in advance.

Re: Dump analysis

«_Superman_»6-Jun-12 22:23

«_Superman_»

6-Jun-12 22:23

It is possible, but without the PDB file, you will have to deal with memory addresses instead of symbols during analysis.
It would take more time and patience, but it is definitely possible.
All the best. Smile | :)

«_Superman_»
I love work. It gives me something to do between weekends.

Microsoft MVP (Visual C++)

Polymorphism in C

Re: Dump analysis

HungryCPPDev11-Jun-12 20:23

HungryCPPDev

11-Jun-12 20:23

Hi,
is there any good tutorial on how to analyze hang dump when there is no PDB. I googled but failed to get good one.

Thanks for your help

Re: Dump analysis

Erudite_Eric6-Jun-12 22:32

Erudite_Eric

6-Jun-12 22:32

To a certain extent, yes.

You need to set windbg to use Microsofts public symbol server, look in Windbg Help for symsrv.

this will suck down pdbs for all MS components leaving yours and third party ones. Hopefully, you can see in the stack where your code is calling into MS code and therefore what part is hanging.

of course you should archive all pdb files with the built exes. Smile | :)

==============================

Nothing to say.

jiuyejii6-Jun-12 0:45

Re: What's problem of my code?( create a random maze)

6-Jun-12 0:45

C++

#include <iostream>
#include <stdlib.h>
#include<ctime>
using namespace std;

void makebg(char**&);

bool Is(int ,int );

void cmaze(int,int);


void count(int,int);

int M=0;
int N=0;
int in=0;
int out=0;
char  **maze; 
int c=0;
int *cti;
int *ctj;
int dir =1;

int main()
{

    cin>>M>>N;
    maze =new char*[M];
    for(int i=0;i<M;i++)
        maze[i]=new char[N];
    cti =new int[M*N];
    ctj =new int[M*N];
    for(int i=0;i<M*N;i++) 
    {
        cti[i]=0;
        ctj[i]=0;
    }

    makebg(maze);

    return 0;
}

void makebg(char **&maze)
{ 
    int   i,j; 


    for(i=0;i <M;i++) 
        for(j=0;j <N;j++) 
            maze[i][j]='#';

    srand((unsigned)time(0));

    in=rand()%(M-2)+1;       // Create entrance or exit 
    maze[in][0]='.';

    out=rand()%(M-2)+1;

         cti[0]=in;
         ctj[0]=1;
    cmaze(in,1);

} 

void cmaze(int i,int j){

    int ran=rand()%4; 


    if((i==out&&j==N-2))      //if then out the recursion
    {
        maze[i][j]='.';
        maze[i][j+1]='.';
    }


    if(maze[out][N-1]=='.')
        return;

    else{

        maze[i][j]='.';

        for (int s=0;s<M;s++)
        {
            for (int t=0;t<N;t++)
                cout<<maze[s][t]<<' ';
            cout<<'\n';
        }
        //system("cls");


        switch(ran)
        {
        case 0:{ //down
                
            if(Is(i+2,j)&&Is(i+1,j-1)&&Is(i+2,j+1)){ //To ensure that the next three sides wall and not backtrack
                i++;
                count(i,j);
                dir=2;
            } 

            else if(i+1==M-1) {               //step return
                c--;
                i=cti[c];
                j=ctj[c];
                cti[c+1]=0;     

                ctj[c+1]=0;

            }
            break;
               }   
        case 1:{ //left
            if(Is(i,j-2)&&Is(i+1,j-1)&&Is(i-1,j-1)){ 
                j--;
                count(i,j);
                dir=3;

            } 

            else if(j-1==0){          
                c--;
                i=cti[c];
                j=ctj[c];
                cti[c+1]=0;

                ctj[c+1]=0;

            }
            break;
               } 
        case 2:{ //up
            if(Is(i-2,j)&&Is(i-1,j-1)&&Is(i-1,j+1)){ 
                i--;
                count(i,j);
                dir=0;

            } 

            else if(i-1==0){             
                c--;
                i=cti[c];
                j=ctj[c];
                cti[c+1]=0;

                ctj[c+1]=0;
            

            }
            break;
               } 
        case 3:{ //right
            if(Is(i,j+2)&&Is(i-1,j+1)&&Is(i+1,j+1)){ 
                j++; 
                count(i,j);
                dir=1;
            }

            else if(j+1==N-1){              
                c--;
                i=cti[c];
                j=ctj[c];
                cti[c+1]=0;

                ctj[c+1]=0;
    
            }
            break;
               } 

        }
        dir=ran;
        cmaze(i,j);

    }

}
void count(int i,int j)
{
    c++;        //       
    cti[c]=i;   //
    ctj[c]=j;   //Record the location

}


bool Is(int i,int j)        
{
    if(i>=0&&i<=M-1&&j>=0&&j<=N-1&&maze[i][j]=='#')
        return true;
    else
        return false;
}

what's the problem of my code?? can't create the maze.
may be problem comes from back to previous step,but how to correct it?

C^hris L^osinger6-Jun-12 1:14

C^hris L^osinger

6-Jun-12 1:14

jiuyejii wrote:
what's the problem of my code??

what happens when you run it?

image processing toolkits | batch image processing

Re: What's problem of my code?( create a random maze)

jiuyejii6-Jun-12 1:36

Re: What's problem of my code?( create a random maze)

6-Jun-12 1:36

the error : stack overfow ,or can not return to the previous step so can't find the exit

David Crow6-Jun-12 2:36

David Crow

6-Jun-12 2:36

jiuyejii wrote:
what's the problem of my code?? can't create the maze.
may be problem comes from back to previous step,but how to correct it?

You seriously need to learn to use the debugger to help solve such problems. Dumping a boatload of code in a forum and asking others to wade through it will get you nowhere.

Instead of trying to solve the problem as a whole, break it down into smaller chunks. If stack space is being exhausted, you most likely have a recursion problem.

"One man's wage rise is another man's price increase." - Harold Wilson

"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons

"Show me a community that obeys the Ten Commandments and I'll show you a less crowded prison system." - Anonymous

Re: What's problem of my code?( create a random maze)

Maximilien6-Jun-12 2:46

Maximilien

6-Jun-12 2:46

did you debug with a small maze size?
do you check array boundaries ? (for example in function count ).

You should try to convert the recursion to a iterative (loop); it might help fix the stack overflow.

Watched code never compiles.

Re: What's problem of my code?( create a random maze)

Aescleal6-Jun-12 6:47

Re: What's problem of my code?( create a random maze)

6-Jun-12 6:47

No idea what's causing your stack overflow, but as one of the previous posters mentioned (think it was David, sorry if I've got that wrong) it's probably related to recursion.

As to what the problem is with your code I can sum that up in one word. Abstraction. There's not a lot is there? When you write huge lumps of code how are other people meant to follow what you mean? Come to think of it how are you supposed to be able to follow it next week? And if you and other people are having problems think of the poor, literal minded compiler, he's having a nightmare [1].

So even if you don't want to do the whole OO thing, think about splitting your code up into nice little packets you and the rest of the world can understand. Here are some guidelines which have served me well:

- make each function only do one thing but make it do it well
- split loops and complex conditionals out into their own functions
- if a variable name is only a couple of characters long it's almost always too short
- if you've got more than 2 levels of indirection in an expression then that's too much. If you've got 2 it's probably still too much. Things like char **& are right out
- even if you're programming in "C like" C++ don't play about with memory directly. Let someone else do the heavy lifting. std::vector, std::unique_ptr and std::shared_ptr can cover about 99% of your dynamic memory requirements.

Interestingly you've got one complex conditional in it's own function. Cool! Keep that up and look for other places you can do the same sort of thing. FREX you've got the following segment of code:

C++

c--;
i=cti[c];
j=ctj[c];
cti[c+1]=0;

ctj[c+1]=0;

in four places. Think of a name to describe what this lot is up to and pack it away in a function. Do that a few more times and you might be starting to see where your code is going wrong.

[1] I've committed a cardinal sin here, I've anthropomorphised a computer. They don't like it when you do that.

Peter_in_27806-Jun-12 17:37

Peter_in_2780

6-Jun-12 17:37

Aescleal wrote:
I've anthropomorphised a computer. They don't like it when you do that.

No wonder OP has a stack overflow, with recursion like that! Poke tongue | ;-P

Cheers,
Peter

Software rusts. Simon Stephenson, ca 1994. So does this signature. me, 2012

Re: What's problem of my code?( create a random maze)

jiuyejii6-Jun-12 18:49

Re: What's problem of my code?( create a random maze)

6-Jun-12 18:49

Thank you for your advice

Aescleal6-Jun-12 23:52

Re: What's problem of my code?( create a random maze)

6-Jun-12 23:52

Any time!

Stefan_Lang8-Jun-12 4:19

Stefan_Lang

8-Jun-12 4:19

The problem is right at the end of the function cmaze(): there you call the same function, recursively. That means for every step, your program will push one more function call on the stack, and it won't resolve it until the very end.

Don't do that kind of thing. Instead use the return code to indicate whetehr or not you need to do another step, and create a loop:

Change the function cmaze to:

C++

bool cmaze(int& i, int& j) {
   //...
   // change your test for the exit to the following:
   if (maze[out][N]=='.')
      return false;

   // ... the rest of your code

   // and at the end:
   return true;
}

Change your call to cmaze in makebg() to:

C++

i = in;
j = 1;
while (cmaze(i, j));

Re: What's problem of my code?( create a random maze)

jiuyejii8-Jun-12 17:57

MFC application being compiled on VS2012

8-Jun-12 17:57

You are right and your suggestions let me learn more,thanks

YaronNir5-Jun-12 23:03

YaronNir

5-Jun-12 23:03

i took an MFC application written in VS2010
opened in in win8 with visual studio 2012
got the following errors:
error C1083: Cannot open include file: "tmschema.h": No such file or directory (afxwin.h)

it returns in several cases

anyway can help?
thanks

Interface basics click here :
http://www.codeproject.com/com/COMBasics.asp

don't forget to vote Smile | :)

David Crow6-Jun-12 2:37

David Crow

6-Jun-12 2:37

YaronNir wrote:
anyway can help?

Does tmschema.h exist?

YaronNir6-Jun-12 2:40

YaronNir

6-Jun-12 2:40

actually you are right, it doesn't

will check more
thanks

Interface basics click here :
http://www.codeproject.com/com/COMBasics.asp

don't forget to vote Smile | :)

tldcolli4-Aug-12 3:31

tldcolli

4-Aug-12 3:31

Strangely, at Microsoft.com, the current link to the Microsoft Windows SDK appears to be broken:

http://msdn.microsoft.com/en-us/windows//bb980924.aspx?wt.svl=more_downloads[^]